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		<H2><A NAME="HDRCONSERV" ></A>9.3 Connecting to the Server
</H2>
		<A NAME="IDX873"></A><A NAME="IDX874"></A>
<A NAME="IDX875"></A>
<P>
Before you can execute a visual program, your workstation must have established
connection to the server.
When you start Data Explorer, the program automatically starts the server
connection, unless you specified that only the user interface
was to be started.
However, if for some reason your workstation becomes disconnected
between the time you start Data Explorer and the time you are ready to
run a program, you must reestablish connection with the
server.
<P>
To start the server connection, select the <TT><STRONG>Start
Server...</STRONG></TT> option from the
<TT><STRONG>Connection</STRONG></TT> pull-down
menus in the VPE or Image
window.
A dialog box appears (<A HREF="#FIGSERVCON">Figure 81</A>).
<P><B><A NAME="FIGSERVCON" HREF="../usrguide.htm#FT_FIGSERVCON">Figure 81. Start
Server Dialog Box</A></B><BR>
<B><BR><CENTER><IMG SRC="../images/strtsrv.gif" ALT="{ Start Server Dialog Box
}"></CENTER><BR></B><BR>
<P>
The Hostname field, by default, contains the name "localhost."
If the DXHOST environment variable or the
<TT><STRONG>-host</STRONG></TT> argument was
specified, this field contains the
setting of that variable.
<P>
You can change the Hostname field by clicking on it and typing in the
new name.
When it displays the desired name, connect to the server by clicking on
the <TT><STRONG>Connect</STRONG></TT> button.
<P>
To change the options associated with starting the server, click on the
Options... button.
This opens the <TT><STRONG>Options...</STRONG></TT> dialog box
(<A HREF="#FIGSERVOPT">Figure 82</A>).
Most of the time, it is not necessary to use these options.
<P><B><A NAME="FIGSERVOPT" HREF="../usrguide.htm#FT_FIGSERVOPT">Figure 82. Start
Server Options Dialog Box</A></B><BR>
<B><BR><CENTER><IMG SRC="../images/strtsrvo.gif" ALT="Figure strtsrvo not
displayed."></CENTER><BR></B><BR>
The fields of this dialog box are as follows:
<TABLE CELLPADDING="3">
<TR VALIGN="TOP"><TD><P><B>Executive
</B></TD><TD><P>Specifies the name of the executive to run.
You might change this field if you want to run a customized version of
Data Explorer.
</TD></TR><TR VALIGN="TOP"><TD><P><B>Working Directory
</B></TD><TD><P>Specifies the default directory to search for files.
</TD></TR><TR VALIGN="TOP"><TD><P><B>Memory Size
</B></TD><TD><P>Specifies the amount of memory to use, in megabytes.
</TD></TR><TR VALIGN="TOP"><TD><P><B>Options
</B></TD><TD><P>Specify options in this text box as you would on the command
line
when invoking Data Explorer;
that is, each option must be preceded by a dash.
<P>
<TT><STRONG>-cache on</STRONG></TT> saves the state of the visual program in
memory
after an execution.
If the visual program changes, Data Explorer reexecutes only the portion of the
program
affected by the change.
If <TT><STRONG>-cache off</STRONG></TT> is specified, Data Explorer must
reexecute the entire
program for each change.
(The default setting is on.)
<P>
<TT><STRONG>-trace on</STRONG></TT> displays each execution step, as it happens,
in the <TT><STRONG>Debug</STRONG></TT> window.
It is mainly used for debugging purposes.
(The default setting is off.)
<P>
<TT><STRONG>-log on</STRONG></TT> saves all communication between the server and
the user interface to a file.
(The default setting is off.)
<P>
Other options are listed in <A HREF="usrgu074.htm#HDRCMDLOPT">C.2 , "Command
Line Options"</A>.
</TD></TR><TR VALIGN="TOP"><TD><P><B>Connect to already running server
&nbsp;radio button&nbsp;
</B></TD><TD><P>Specifies that the user interface should connect with a server
that was started earlier.
<P>
You might use this option to set up a connection to a debugging session
for a customized version of the Data Explorer executable.
You can specify the port number in using the stepper below the button.
Note that when this button is toggled on, all other fields in this
dialog box become disabled.
</TD></TR></TABLE>
<P>
<H3><A NAME="HDRRSTSRV" ></A>Resetting the Server
</H3>
<A NAME="IDX876"></A>
<A NAME="IDX877"></A>
<P>
If the data set your visual program is using changes (e.g., by being edited)
during your Data Explorer session, and the <TT><STRONG>cache</STRONG></TT> is
enabled
(the default condition), it may be necessary to force Data Explorer
to reinitialize the server executive to access the
new data.
To do this, select the <TT><STRONG>Reset Server</STRONG></TT> option from the
<TT><STRONG>Connections</STRONG></TT> pull-down menu.
<P>
The action of resetting the server flushes the executive cache.
The next time you execute the visual program, it executes the entire network,
not
just the portions affected by changes internal to the Data Explorer session,
and will thus reaccess the data set.

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